“Healthy” pre made meals

Define "healthy".

I use these a fair bit, although I have a disability that makes meal preparation a risk activity, so it's on medical instructions. That's at least some assurance that they won't kill me, and I do like to mix in my own vegetables or other bits as required.

Eating "healthy" pre-made meals will not necessarily make you lose weight. If you burn 2500 calories a day but you eat 2600 calories of broccoli a day you will gain weight (and also be miserable). If you eat only 2400 calories a day of Crunchie bars you will lose weight, aside from edge cases (like a thyroid issue) this is the only thing you need to know if your goal is weight loss.

There was a professor of nutrition in America who ate nothing but junk food supplemented by some vitamin tablets and lost 27 pounds all because he restricted his calorie intake down to 1800 per day.

If your goal is to lose weight you need to enter into a calorie restricted diet that also covers your other macros like protein, fibre, and vitamins. What you actually eat to achieve this is largely irrelevant, anyone who tells you otherwise is trying to sell you something.

By "no shite" I presume you mean no Ultra-processed food (UPF), which is designed in a lab and the human body is not properly equipped to handle. There's a reason why you can't stop yourself once you pop open that pack of MSG coated modified potato starch and the book Ultra-Processed People does a great run down on the history and health effects of the industry. The more of these you can avoid the better for your overall health but again if your goal is purely weight loss these don't matter.

The only thing I will say is there is evidence that higher salt/sodium levels leads to additional water retention in the body which will increase your weight and pre-made meals of all kinds tend to be much higher in salt than a meal you would make yourself, but this is not fat gain and can be lost easier through controlling your salt intake at the end of your cut.

So yeah, find a pre-made meal that you like the taste of and just eat that while also tracking your calorie intake over the day.

There has been good advice so far. I am no dietician / nutritionist and everyone's metabolism is its own ball game. For that reason I won't try to answer questions such as "Should my diet consist of 70% protein, 20% fibres and 10% carbs?" because the science becomes very complex and unfriendly to laypeople. Instead, here's some food for thought:

1. Cut out snacking

Excessive snacking may be a sign that your body is craving nutrients so instead of eating more you ought to rethink your base meals. Grouping calories together helps protect your enamel as well.

2. Think of food as an investment

If you have more nutrient-dense (yet seemingly more expensive) meals you may end up spending less money than you otherwise would. Read labels. Where does this food come from? Look for logos such as Guaranteed Irish, Bord Bia, Love Irish Food. In terms of accuracy, the Bord Bia shamrock is your foremost guide for produce and meats. The other two are useful but also assess unrelated metrics such as impact on the local economy and make exceptions for ingredients that can't be sourced in Ireland. If it's ultra-processed, does the packaging say the meat is local?

3. Keep it simple

You can't go wrong with eggs, salmon, beef, chicken breast, oats, milk as long as they are produced, reared, slaughtered etc. here using local and organic ingredients. There's a whole ecosystem that affects the quality of your food, which leads to my final point.

4. Focus on quality

Obviously you are aware of such terms as proteins, fibres, carbs, sugars and so forth. What may be less apparent is that there is low-quality vs high-quality protein. You may wish to refer to methods like DIAAS for a better overview. Fundamentally, if you ingest the latter kinds of essential nutrients chances are you will have fewer issues with your diet.

Ultra-processed food isn't inherently unhealthy, it's just that the more processed it is, the more strenuous it becomes to evaluate its nutritional impact. One solution would be to make food processors more efficient, more transparent and less wasteful but obviously that would be a massive undertaking.